Circuit controlling mechanism



Sept. 1, 1931. E. A. MAU 1,821,559

CIRCUIT CONTROLLING MECHANISM Filed Oct. 14I 1925 Patented Sept. l, 1931 v UNITED STATES PATENT OFFICE EDWARD A. MATT, or NEW BRITAIN, CONNECTICUT, AssTeNOE. TO LANDERs, FEAEY a CLARE, OE NEW BRITAIN; CONNECTICUT, A COEPORATIONOE CONNECTICUT cmcu'rr CONTEOELTNG NECTTANISM Application vledetober 14, 1925. Serial No.' 62,373.

.this spring being placed -under tension by the rotation of the button until it reaches a given tension whereupon it snaps the contact arm from one position to another. Even in such switches, however, some arcing occurs, particularly in heavy duty switches, and this arcing is destructive to the switch mechanism. 1

It is an object of the present invention to provide a circuit controlling mechanism suclrthat the customary type of snap button switch may be utilized in making and breaking circuits without any arcing.

With this general Object, and others in'- view, the invention consists in the features, combinations, and details of construction and arrangements ofL parts which will lfirst be described in connection with the 'accompanying drawings and then more particularly pointed out.

In the drawings.

Figure 1 is a perspective view of a circuit controlling mechanism constructed in accordance with the invention;

Figure 2 is a similar view showing the parts in different position;

Figure 3 is a schematic and diagrammatic view of the switch and wiring; and,

Figure 4 is a diagrammatic view of a modified construction. p

As later appears in detail, the current to the energy-utilizing device, e. g. a resistor, is controlled by a switch of the contactorterminal type and which may, for convenience, be designated a hand switch. Associated with this switch is a master switch that automatically causes a break in the main circuit during the makes and breaks of the hand switch. While the hand Jswitch mayy be O 'any desired construction,1`t may conveniently be a snap switch of standard type.

Referring to the drawings, Figs 1-3 illustratean embodiment of the invention in which the hand switch is a multiple switch of the type which rangements and off This type of switch is commonly utilized in heating appliances, e. g. hot plates. By controlling individual branch circuits the switch gives high, medium and low heats and olif and is known as a three heat switch. The Aparticular switch here illustrated as an example comprises a spindle 21 on which is mounted a handle or operating button 22. Freely rotatable about the spindle is a contactor unit comprising two spiders hereinafter referred to. The contactor unit is rotated indirectly by the button and spindle through a spring device givinga snap action. To this end, mounted on the spindle to rotate therewith are two spaced housing plates 25, 26, connected by a bridge piece 27. Wound around the spindle, and enclosed by the plates, is a spring 29, its two ends extending radially Outward beyond the rims of the housing plates. In normal position these ends straddle the bridge 27 which serves as a tensioning abutment. They also straddle a lug 30 rigidly connected with the contactor unit. When the 'button is actuated, the rotation of the spindle moves lug 27 against one end of the spring. This may be either end as the switch; operatesfin either direction.

The other end of the spring bears against lug 3Q but owing to the friction between the contactor and terminals this pressure is ineffective until the spring attains a given tension. The movement of the bridge 27, therefore, moves one springend away from the other, thereby winding up the spring, this continuing until a given spring tension is attained. During this tensioning movement the contactor unit is stationary. Upon a given tension being attained the friction is overcome and the end of the spring which is pressing against lug 30 gives three circuit ar`l 7 now rotates the contactor unit in the direction of .spindle movement with a snap action,the extent of movement being limited by the new engagement of contactor and terminals. The first spring end, during this operation, has been moved slightly further than the angular movement of lug 30. Consequently when the button is released there is a slight retrograde movement of the spindle unit until the forward `spring end moves back to engagement with lug 30. The parts are now all displaced angularly but have the same relative position as before.

angle of displacement is 90.

The contactor unit carries two contactor plates or spiders located in offset planes.

cated in planes to correspond with the contactor arms. The rear set comprises a top terminal 40 and a left side terminal 41 located 90 apart. The front set comprises a bottom terminal 42, a right side terminal 43 and a left side terminal 44, the two latter each being located 90 apart from the bottom terminal and 180 apart from each other. Left side terminal 41 of the rear set and left side terminal 44 of the front set have a common bus bar 45. Line wires 46, 47 connect with top rear terminal 40 and bottom front terminal 42, respectively.

While the energy-utilizing device mayl` vary, the drawing shows a stove or hotplate 15 heated by resistors 16, 17 enclosed in a housing 18 below the hot-plate, these resistors being indicated diagrammatically in Fig. 3. A conductor 11 connects one end of resistor 16 with the top rear terminal 40. A conductor 12 connects one end of resistor 17 with bus bar 45, thereby connecting` it with both left side terminals 41, 44. A conductor 13 connects the other ends of both resistors to right front terminal 43.

Fig. 3 shows, diagrammatically, the parts in off position. As terminal 42, connected with line wire 47, is disconnected, no current passes.

For low heat the contactor unit is rotated 90 counter-clockwise from off position. In this position contactor arms 37, 38 bridge terminals 44, 42, the other contactor arms being disconnected. This arrangement connects the two resistors 16, 17 in the circuit in series, the circuit being traced from line wire 47, through terminal 42, front contactor spider 36, terminal 44,

In the switch here shown th bus bar 45, conductor 12, resistor 17, resistor 16, conductor 11, and terminal 40 to line wire 46. I

- For high heat the contactor unit is moved 180 from low heat, or, in other words, 90 from off position clockwise. In this osition, rear contactor arms 34, 35 bri ge terminals 40, 41 and front contactor arms 37, 39A bridge terminals 43, 42, arm 38 being out of contact. This connects the resistors in circuit in parallel. The circuit is traced from line wire 47 through terminal 42, front contactor spider 36, and terminal 43 to conductor 13. From the latter the circuit splits, one branch being traced through resistor 16, conductor 11, and terminal 40 to line wire 46, the other traced through resistor 17, conductor 12, bus bar 45, terminal 41, rear contactor spider 33, and terminal 40 to line wire 46.

For medium heat, the contactor unit is moved to a position 180o from off. In this position, front contactor arms 37, 38, 39 bridge terminals 42, 43, 44. Rear contactor arm 35 is in contact with terminal 40 but arm 34 is unconnected. In this position the resistor 16 is connected in the circuit. The circuit is traced from line wire 47 through terminal 42, front contactor spider 36, terminal 43, conductor 13, resistor 16, conductor 11, and terminal 40 to line wire 46.

Except for the spindle extension hereinafter referred to, the switch construction and wiring arrangement above described are known in the art and are of more or less standard construction.

There is provided means for causing the circuit to be broken during the make or break of the switch contacts. This may be accomplished by a master switch in the main circuit and operated by the actuation of the switch button. That is, it is operated to open the circuit during the delay in the switch action between the start of the button movement and the snap of the contactor unit; and to close the circuit again following the snap of the contactors. Although capable of various constructions, in that here shown as an example, connected in the main circuit, e. g. in line wire 46, is a master switch in the form of a mercury tube switch 55. This latter comprises a tube having two depending recesses 56, 57 into which eX- tend terminals 58, 59 connected in series in the line wire 46. The tube contains a `volume of mercury 54 capacitatcd to connect the two terminals 58, 59 when the tube is horizontal and to disconnect the terminals when the tube is tilted out of the horizontal. The tube 55 is mounted in a clip 60 secured in a cradle 61. In normal position (Fig. 1) the tube is horizontal and the mercury connects the two terminals, thus completing the circuit through the tube. Vhen, howl the lower end of the tube and there is a break between the terminals, whereby the main circuit is broken. v

The cradle is rocked to tilt the tube into oii" position and retilted to on position portion for wiping contact with the lever.

In normal position, a fiat or low portion of the cam is presented to the lever, the lever being held to the cam by a spring 66. In this position (Fig. 1) the tube is horizontal. When the spindle rotates the cam, a corner of the cam wipes against the lever to actuate `the same, thus tilting the tube'to open circuit position. In the articular construction shown the throw o the spindle during the delayed action is such as to wipe two cam corners against the lever. Thus an intermediate flat portion is presented which allows the tube to retake horizontal position during the cycle but this maybe disregarded. The parts are so arranged that the second corner of the cam has displaced the lever and tilted the mercury tube switch just prior to the snap'action of the hand switch. That is, at the time the switch contactors leave their terminals and engage another set, the tube is in circuit-breaking position (Fig. 2).. As a result, when the hand switch contacts are breaking and making, the main circuit is broken. As there is.-

' grade movement of the spindle into its new normal position. Upon this retrograde movement the cam is displaced reversely toA present a Hat portion to the lever. Consequently, as the cam high point withdraws,

the lever returns to normal position andretilts the tube to horizontal, thus closingl the main circuit again.

Since the action of the spindle is the same for each circuit-controlling movement of the hand switch, the main circuit is broken and closed again leverytime the hand switch is operated, the break being prior to the break -in the hand switch and the make being subsequent to the make in the hand switch. lAs above stated,- the hand switch is operable in either direction and as cam 65 is symmetrical with respect to the spindle, its operation is the same for either direction of spindle movement.

The invention may be embodied ina sim-f ple on-and-of switch., For example, the switch shown may be modified by removing the front-contactor spider, and connecting'the line twires to terminals 40,41, any energy-utilizing device being lplaced' in the line. With such modification the switch operates in the same way mechanically and for each actuation of the button the mercury tube switch functions as described.

In the embodiment first described, the

master switch is in a niainficircuit having a number of branch circuits controlled by a single compound switch. The invention in its entirety includes a master switch in a main circuit having a number of branch circuits controlled by individual switches, either simple or compound. For example, the mercury tube switch may be placed in the main circuit of a stove having a plurality of hot-plates, each having a switch duplicating the switch first described or a simple switch. This may be accomplished by providing a cam for each switch unit, the several cams lying in a straight line, and by extending the length of the lever to cover all the cams. Such a construction is indicated more or less -diagrammatically inFig. 4. As here shown as an example, a lever 71 is provided which is like lever 63 except that its base portion is longer. Below the lever 7l are three cams 72, 73, 74 each a duplicate of cam 65, mounted on the respective' spindles of three independent hand switches. For convenience of illustration simple onand-ofi' switches 75, 76, 77 and single resistors 78, 79, are indicated, but it will be apparent that multiple switches and threeheat wirings like the unit iirst described may be substituted. In the main circuit is a mercury tube switch 55. like that described and mounted as described to be tilted by the lever Whenever any one of the hand switches is actuated the corresponding `cam operates the lever 71 to tilt the mercury tube switch in the manner described. Thus, for any actuation of any hand switch, there is no load on the handswitch during the break or make of the contacts and so there can be no arcing. In this latter construction, since the main circuit is broken for each operationof any hand switch, it may happen that the main circuit is broken while one branch circuit is closed for duty. Such a break, however, is so brief as tobe inconsequential. Itis obvious that each unit may have its own mercury tube switch if desired. The operation of the device will be clear from the above without further description. With the constructions described the life of the hand rswitch is prolonged by avoiding the destructive eifects of arcing, and the master switch, except for mechanical break- 'age of the tube, is practically indestructible. Further, the prevention of arcing is effected in such a way as to enable standard type hand switches to be utilized.

What I claim is:

1. In a switch for controlling a circuit the combination of terminals, a movable contactor for contacting with said terminals, a rotatable spindle and a spring connection ating the latter with a delayed snap action upon rotation of the spindle, and means actuated b said spindle and operable during fsuch de ay for causing the circuit to be broken before such operation of the contactor and closed after such operation.

2.l In a switch for controlling a circuit the combination of terminals, a movable contactor for contacting with said terminals, a rotatable spindle, and a spring connection between the spindle and contactor for operating the latter with a delayed snap action upon rotation of the spindle and for permitting al retrograde movement of the spindle following the movement of the contactor, and means actuated by said spindle for causing said circuit to be broken during said delay in the switch action and to be closed again during said retrograde movey ment of the s indle.

3. In a switch for controlling a' circuit the combination of terminals, a movable contactor for contacting with said terminals, a rotatable Spindle, and a spring connection between the spindle and contactor for operating the latter with a delayed snap action upon rotation of the spindle and for permitting a retrograde movement of the spindle following the movement of the contactor, a mercury tube switch in said circuit, and a connection between said mercury tube switch and the spindle for tilting the mer` cury tube switch into open circuit position during said delay and retilti'ng it to closed circuit position upon said retrograde movement. D v

In testimony whereof, I have hereunto set my hand.

EDWARD A. MAU.

between the'spindle and contactor for oper- 

